Performance analysis of ETDGE – an efficient and unbiased TDOA estimator

Abstract

A computationally efficient estimator is proposed which can provide instantaneous delay measurement for many practical applications such as radar, sonar and geolocation via satellites. It consists of an adaptive FIR filter to model the time difference of arrival (TDOA) between the received signals from two sensors and a variable gain to adapt to the changing signal-to-noise ratio environment. The TDOA is obtained directly on a sample-by-sample basis and no interpolation is necessary. The proposed algorithm gives an unbiased delay estimate, and its performance for both stationary and nonstationary conditions is evaluated rigorously, It is also proved that the least-squares realisation of the estimator attains the Cramer-Rao lower bound.